.\" -*- nroff -*-
.\" Copyright 2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" $COPYRIGHT$
.TH MPI_Add_error_class 3 "Jun 10, 2020" "4.0.4" "Open MPI"

.SH NAME
.nf
\fBMPI_Add_error_class\fP \- Creates a new error class and returns its value

.fi
.SH SYNTAX
.ft R

.SH C Syntax
.nf
#include <mpi.h>
int MPI_Add_error_class(int *\fIerrorclass\fP)

.fi
.SH OUTPUT PARAMETERS
.ft R
.TP 1.4i
errorclass
New error class (integer).
.ft R
.TP 1.4i
IERROR
Fortran only: Error status (integer).

.SH DESCRIPTION
.ft R
The function MPI_Add_error_class creates a new, local error
class.

.SH NOTES
.ft R
Because this function is local, the same value of \fIerrorclass\fP may
not be returned on all processes that make this call, even if they
call the function concurrently. Thus, same error on different
processes may not cause the same value of \fIerrorclass\fP to be
returned. To reduce the potential for confusion, MPI_Add_error_string
may be used on multiple processes to associate the same error string
with the newly created \fIerrorclass\fP. Even though \fIerrorclass\fP
may not be consistent across processes, using MPI_Add_error_string
will ensure the error string associated with it will be the same
everywhere.
.sp
No function is provided to free error classes, as it is not expected
that an application will create them in significant numbers.
.sp
The value returned is always greater than or equal to MPI_ERR_LASTCODE.

.SH ERRORS
.ft R
Almost all MPI routines return an error value; C routines as
the value of the function and Fortran routines in the last argument. C++
functions do not return errors. If the default error handler is set to
MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
will be used to throw an MPI::Exception object.
.sp
Before the error value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job, except for
I/O function errors. The error handler may be changed with
MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN
may be used to cause error values to be returned. Note that MPI does not
guarantee that an MPI program can continue past an error.

.SH SEE ALSO
.ft R
.nf
MPI_Add_error_code
MPI_Add_error_string
MPI_Error_class
MPI_Error_string

